人力资本与进城农民工职业选择的实证研究

为适应中国劳动力供求形势新变化,促进社会和谐发展,迫切需要提高进城农民工的职业层次。教育、培训、迁移等人力资本因素是影响进城农民工职业选择的重要因素。使用多元logit模型进行了实证分析。受教育程度越高、接受过培训、在城市工作的年限越长的进城农民工,其从事具有更高社会声望职业的可能性就越大,这些职业有诸如办事人员和生产操作人员、专业技术人员和单位负责人等。提出了加强进城农民工人力资本投资的政策建议。     

中国移动通信业价格竞争本质解析

中国移动通信业的价格竞争,经过了无价格竞争阶段、显性价格竞争阶段、隐性价格竞争阶段、后价格竞争阶段的演化,体现了制度调节与市场选择并行的内在规律性,也增进了市场协调、提高了市场效率。中国移动通信业价格竞争具有非合作博弈的特性,行业管制与市场选择共同推动了竞争的有序化。因此,要实现中国移动通信市场的有效竞争,市场机制的作用是有限的,还离不开适当的政府行政参与下的不对称管制政策,而且不对称管制政策也需要根据市场变化进行调整和改进。     

The Coverage Properties of Confidence Regions After Model Selection

It is very common in applied frequentist (classical) statistics to carry out a preliminary statistical (i.e. data-based) model selection by, for example, using preliminary hypothesis tests or minimizing AIC. This is usually followed by the inference of interest, using the same data, based on the assumption that the selected model had been given to us  a priori . This assumption is false and it can lead to an inaccurate and misleading inference. We consider the important case that the inference of interest is a confidence region. We review the literature that shows that the resulting confidence regions typically have very poor coverage properties. We also briefly review the closely related literature that describes the coverage properties of prediction intervals after preliminary statistical model selection. A possible motivation for preliminary statistical model selection is a wish to utilize uncertain prior information in the inference of interest. We review the literature in which the aim is to utilize uncertain prior information directly in the construction of confidence regions, without requiring the intermediate step of a preliminary statistical model selection. We also point out this aim as a future direction for research.     

Optimal portfolios under worst-case scenarios

In standard portfolio theories such as Mean–Variance optimization, expected utility theory, rank dependent utility heory, Yaari’s dual theory and cumulative prospect theory, the worst outcomes for optimal strategies occur when the market declines (e.g. during crises), which is at odds with the needs of many investors. Hence, we depart from the traditional settings and study optimal strategies for investors who impose additional constraints on their final wealth in the states corresponding to a stressed financial market. We provide a framework that maintains the stylized features of the SP/A theory while dealing with the goal of security in a more flexible way. Preferences become state-dependent, and we assess the impact of these preferences on trading decisions. We construct optimal strategies explicitly and show how they outperform traditional diversified strategies under worst-case scenarios.     

THE IMPACT OF ACADEMIC PATENTING ON THE RATE,QUALITY AND DIRECTION OF (PUBLIC) RESEARCH OUTPUT*

We examine the influence of faculty patenting on the rate, quality, and content of public research outputs in a panel dataset of 3,862 academic life scientists. Using inverse probability of treatment weights (IPTW) to account for self‐selection into patenting, we find that patenting has a positive effect on the rate of publications and a weak positive effect on the quality of these publications. We also find that patenters may be shifting their research focus to questions of commercial interest. We conclude that the often voiced concern that patenting in academe has a nefarious effect on public research output is misplaced.     

信贷配给理论及其对中国银行业改革的启示

在商业银行占据主导地位的发展中国家中 ,由于现存金融市场的种种结构缺陷以及银行体系内外部建设的不完善 ,在发育成熟的金融市场出现以前 ,政府将被迫肩负着维持对银行部门部分控制的义务。     

Integrating ecosystem services into conservation assessments: A review

A call has been made for conservation planners to include ecosystem services into their assessments of conservation priority areas. The need to develop an integrated approach to meeting different conservation objectives and a shift in focus towards human wellbeing are some of the motivations behind this call. There is currently no widely accepted approach to planning for ecosystem services. This study contributes towards the development of this approach through a review of conservation assessments and the extent to which they include ecosystem services. Of the 476 conservation assessments identified by a set of search terms on the Web of Science, 100 were randomly selected for this review. Of these only seven had included ecosystem services, while another 13 had referred to ecosystem services as a rationale for conservation without including them in the assessment. The majority of assessments were based on biodiversity pattern data while 19 used data on ecological processes. A total of 11 of these 19 assessments used processes, which could be linked to services. Ecosystem services have witnessed an increase in attention received in conservation assessments since the year 2000, however trends were not apparent beyond this date. In order to assess which types of ecosystem services and how they have been accounted for in conservation assessments, we extended our review to include an additional nine conservation assessments which included ecosystem services. The majority included cultural ecosystem services, followed by regulatory, provisioning and supporting services respectively. We conclude with an analysis of the constraints and opportunities for the integration of ecosystem services into conservation assessments and highlight the urgent need for an appropriate framework for planning for ecosystem services.     

大型航天企业复杂产品体系的关键技术选择

本文首先总结了复杂产品体系资源结构特性中的技术宽度与技术深度,然后根据已有研究得出航天企业复杂产品体系的群技术选择方法,最后提出了航天企业复杂产品体系技术开发过程中的技术资源选择框架。     

基于生命周期的虚拟企业知识活动分析及其伙伴选择过程研究

随着新经济的到来,知识越来越成为企业快速响应市场机遇和获取竞争优势的最短缺资源。而企业自身知识资源的有限性使企业越来越多地采用虚拟企业的高级形态——知识联盟型虚拟企业来弥补企业知识资源的不足以快速响应变化的市场需求。首先对知识联盟型虚拟企业的知识缺口类型进行研究和划分,然后分析并描述虚拟企业生命周期各阶段的知识活动;在此基础之上,探讨虚拟企业组建阶段考虑知识要素的伙伴选择过程;最后,针对不同的知识缺口,提出伙伴选择过程的评价指标体系设计中应考虑的知识性因素。     

基于会计环境特征的会计准则制定导向选择

近年来,我国的会计准则建设取得了巨大成就,以2006年颁布的新的企业会计准则为标志,我国的会计准则已初步与国际会计接轨。新会计准则执行一年来,其效果受到理论与实务界的普遍关注,又一次兴起了对会计准则的制定导向的讨论,它既是一个理论问题又是一个实践问题,如何选择合理的会计准则导向,不仅关系到会计准则的质量,而且直接关系到会计准则的推广应用。笔者在对我国会计环境特征进行实际调查的基础上,提出了选择会计准则制定导向,必须充分考虑我国的会计环境特征,进而提出了应采用规则导向基础上的原则导向的观点。